Sir: Mirtazapine is a novel antidepressant, known as a noradrenergic and specific serotonergic antidepressant (NaSSA). It is an antagonist of presynaptic α2-autoreceptors and α2- heteroreceptors, resulting in an increased release of both norepinephrine and serotonin, and it also enhances noradrenergic and serotonergic neurotransmission. However, mirtazapine potently blocks 5-HT2 and 5-HT3 receptors. Although there are several studies in the literature that examine the effects of mirtazapine on sleep parameters, further study of larger groups of depressed patients is clearly needed.